In several screens, I saw some crystals that look like protein crystals, but they redissolved and became unapparent during checking them under light microscopy after a few seconds.
For example, in a buffer screen containing 30%v/v PEG400,100mM Tris/HCl and 200mM Li2SO4, a rather big (~0.1mm) triangular star-like crystal became unapparent after about 1 minute.
It is really possible for protein or salt crystals? In the reservoir buffer of this screen, there were several plate-like crystals seeming to be Li2SO4 crystals or PEG400! These were different from the crystals in drop.
Protein crystals are fragile. Such a change in temperature during observation can indeed dissolve a protein crystal; try to observe at cold temperature. On the other hand a salt crystal should be more solid and will resist to moderate heating.
It is absolutely possible for crystals to redissolve when exposed to increase temperatures, dilution of salts, too much cryo, etc. It is a heart-breaking truth that you may dissolve your crystals when trying to cryopreserve. Hopefully your microscope is at the same temperature that your crystallization experiments are. This is partially why you want to recreate the mother liquor for your cryo steps. In some cases, crystals will not form at certain temperatures (I have experienced proteins that only crystallize at 4C and some that only crystallize at 14C).
Yes, you are right, if you have this crystals add an extra wash with water. in addition, these crystals destroy tissues and cells. If your objective is to see the crystals use a low wavelength (350 or lower) to observe them
You need a kind of plate-table, transparent,e to isolate your crystallization box from the temperature generated by your conventional source of light. Or change for a cold source of light for your microscope. Yes, you can dissolve your protein crystals increasing the temperature, by the way, this is one strategy to try when you have too much crystals in a drop, you dissolve more of them increasing the temperature and then you live the temperature go down again. The few one that survive to the higher temperature then will grow faster than the new ones coming. Good luck
To me, this type of crystals is caused from lithium. You can incubate your protein buffer without protein to the same reservoir and see what's going on.
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